The present invention generally relates to metal-oxide-semiconductor field-effect transistors (MOSFET), and more specifically, to gate spacers.
The MOSFET is a transistor used for amplifying or switching electronic signals. The MOSFET has a source, a drain, and a metal oxide gate electrode. The metal gate is electrically insulated from the main semiconductor n-channel or p-channel by a thin layer of insulating material, for example, silicon dioxide or glass, which makes the input resistance of the MOSFET relatively high. The gate voltage controls whether the path from drain to source is an open circuit (“off”) or a resistive path (“on”).
Gate spacers form an insulating film along gate sidewalls. Gate spacers may also initially be formed around “dummy” gate sidewalls in replacement gate technology. The gate spacers are used to define source/drain regions in active areas of a semiconductor substrate located slightly away from the gate.